Ship&#39;s lifeboat davits



Jan. 24, 1967 G. w. HAYCOCK 3,299,452

SHIP S LIFEBOAT DAVITS Filed Feb. 26, 1965 6 Sheets-Sheet 1 Inventor /Z/ GEfikf W 6440 6 06 MW 5 M Attorney Jan. 24, 1967 e. w. HAYCOCK 3,299,452

SHIP S LIFEBOAT DAVITS Filed Feb. 26, 1965 6 Sheets-Sheet 2 l n ventor 650R 55 W 644/(00'1 Atlorney Jan. 24, 1967 e. w. HAYCOCK 3,299,452

SHIP S LIFEBOAT DAVITS Filed Feb. 26, 1965 6 Sheets-Sheet 5 Inventor Gimme W fi m (a :4

Attorney Jan. 24, 1967 G. w. HAYCOCK SHIP'S LIFEBOAT DAVITS 6 Sheets-Sheet Filed Feb. 26, 1965 w 0 r m n nw,A 2/. W 5 W. m8 0v Jan. 24, 1967 G. w. HAYCOCK 3,

SHIP S LIFEBOAT DAVITS Filed Feb. 26, 1965 a Sheets-Sheet 5' Inventor Qfiaeaf W/Z/AJ/C'UCK B qyma M Attorney 6 Sheets-Sheet Filed Feb. 26, 1965 y vwu 2/ Attorney United States Patent 3,299,452 SHIPS LIFEBOAT DAVITS George W. Haycock, Clarkston, England, assignor to said George W. Haycock and John S. Thomson, Greenoch, Scotland Filed Feb. 26, 1965, Ser. No. 435,664 Claims. (Cl. 938) This invention relates to a ships lifeboat davits of the kind known as roller track gravity davits, in which boat supporting and suspending structures have rollers which are adapted to run on roller tracks, under the influence of gravity and usually under the restraint of braking means, from a boat-inboard position whereat the lifeboats are stowed inboard of the ship to a boat-outboard or lowering position at the side of the ship, wherefrom the structures reach out-board so that the lifeboats can be lowered to the embarkation level and thence to the water.

In operation of davits to launch the lifeboats on the higher sides of severely listing ships difficulties have sometimes been exeprienced in manoeuvring the lifeboats over the sides of the ships, due to the inadequacy of the outboard reach of the aforementioned structures under such conditions of severe list.

An object of the present invention is to obviate or at least mitigate the above disadvantage.

According to the present invention there is provided a roller track gravity davit in which a boat supporting and suspending structure comprises a roller carriage movable between a boat-inboard position and a boat-outboard position, a davit arm pivotally mounted on said carriage and movable between a normal launching and an extended-reach launching position relative thereto, latching means for holding the davit arm in said normal-launching position when the carriage is in the boat-inboard position and the boat-outboard position, said latching means being releasable to allow the davit arm to move to said extended-reach launching position when the carriage is in the boat-outboard position, and stop means for holding the davit arm in said extended-reach launching position.

Examples of the invention will now be described, with reference to the a-ccompanying drawings, in which:

FIG. 1 is an end elevation showing under even-keel conditions, one of a companion pair of roller track gravity davits complete with lifeboat.

FIG. 2 is a side elevation corresponding to FIG. 1, and showing the fore part of the lifeboat.

FIGS. 3 and 4 are part end elevations of the davit shown in FIGS. 1 and 2, illustrating its operation against a severe list.

FIG. 5 is a sectional end view of part of the davit shown in the preceding figures, to a larger scale than that of these figures.

FIG. 6 is an end elevation of one of a companion pair of flush deck type roller gravity davits complete with lifeboat, illustrating its operation against a severe list.

Referring to FIGS. 1 to 5, revelant portions of the boat deck, lifeboat-embarkati-on deck, and ships side are shown respectively at 10, 11 and 12.

The roller track, as is usual, comprises a pair of parallelly disposed and mutually in-turned channels 13 which slope downwardly from an inboard mounting 14 on the boat deck to the ships side, where they terminate in sections 13a set in line with the ships side and of sufficient length to accommodate the roller carriage.

The roller carriage comprises two side plates 15 interconnected by a base plate 16 and end plate 17, and it is provided with four flanged-rollers 18 adapted to run within the channels of the track. These rollers are arranged in pairs on the end of two axles 19 and 20, which pass transversely through the side plates near the ends thereof.

The davit arm 21, of usual jib-like form, is pivoted at its lower end on the lower axle 20 of the carriage, and the arm has side buttresses 22 which are engageable with rests 23 on the carriage side plates in order to support the arm in its normal operative position, particularly when the davit is in its boat-inboard position, shown 11 FIGS. 1 and 2.

' The arm and carriage are also interconnected by an articulated tie which forms stop means for limiting the outward pivoting of the arm 21 on the carriage and folds downwardly into a retracted position between the carriage side plates. This tie consists of two links 24 and 25 pivotally united by a pin 26 and, at their distal ends, pivotally connected respectively by a pin 27 to lugs 28 formed on the arm and to the upper axle 19 of the roller carriage. The tie of course need not be articulated but could be otherwise retractable.

There is also provided latching means for preventing pivotal movement of the davit arm 21 in normal use of the davit, said means comprising a hooklike coupling 29 which is pivotally connected to the lugs 28 of the arm and which is mounted on the pin 27 and is adapted to engage, when the arm is in its normal operative position, a cross bar 30 fixed between the upper ends of the carriage side plates. This coupling straddles that end of the link 24 with which it is co-pivotal, and the said link end has a formation 31 for supporting the coupling when the arm is outwardly displaced from the carriage, and for suitably positioning the coupling for automatic engagement with the cross-bar whenever the arm is brought into its normal, operative position. For this latter purpose the coupling is formed with a nose-piece 32 for lifting the hook thereof over the cross-bar preparatory to its falling into engagement therewith.

Further, the coupling has an abutment 33 which is engageable by a push-rod 34 slidably carried in guides 35 on the underside of the carriage.

The push-rod 34, in turn, is engageable by a trip consisting of a stop 36 mounted on a spindle 37 which is journalled in bearing brackets 38 secured to the roller track near the foot thereof. This spindle is provided with an operating handle 39 whereby the stop can be turned either into contact with, or clear of, a pair of upwardly projecting *abutments 40 carried by a strap 41 on the roller track. When the stop is in contact with the abutments the trip is in its operative position, since the pushrod is engageable by the stop. Otherwise the trip is in an inoperative position and the lower part of the push rod can pass freely betwen the abutments.

The pulley system, on which the fall rope 42 of the davit is trained, consists of three pairs of pulleys 43, 44 and 45 mounted on the arm 21 and a pulley 46 mounted at the top of the roller track. The pulleys comprising each pair are co-axially arranged, one on each side of the arm and with the three pulleys thus disposed on each side of the arm in alignment with each other. The three pairs of pulleys are located on the arm respectively at an appropriate radius from the lower axle 20 of the carriage, at the bend of the arm, and at the upper end of the arm, and the pulley 46 is mounted substantially in alignment with the pulleys on one side of the arm.

The winch-cum-brake unit 47 of the davit is attached to the inboard mounting 14 on the boat deck, and this unit is of a double-type adapted to operate the davit in unison with its companion.

The fall-rope 42, as is usual, is trained as a loop suspending a pulley-block 48 from the upper end of the davit arm, this loop having parallel runs which stretch, on the one hand, from the winch-cum-br-ake unit over the pulley 46 to one .side of the davit arm, and, on the other hand,

from an anchorage (not shown) at the top of the roller track to the other side of the arm. On both sides of the arm the parallel runs are trained under the pulleys 43 and over the pulleys 44 and 45, finally terminating in the loop-end at the pulley-block.

As is customary, the pulley-block is detachably connected, by means of the chain 49, to the appropriate suspension-hook 59 of the lifeboat 51, as shown in FIG. 2.

The davit arm is formed with the usual keel-support 52 for the boat, and is provided with the usual slip-hook 53 for the pulley-block and side-support 54 for the boat. In addition to the foregoing, the davit arm has a top projection 55 which is adapted to contact the top of the pulley-block and thereby support the arm under certain conditions hereinafter explained.

Releasable means, for securing the roller carriage, arm and lifeboat in the boat-inboard position would be provided on the davit. Such means are well-known and, accordingly, are not shown in the drawings.

In general, operation of davits as hereinbefore described is carried out in the manner common to their kind, the carriage and arm assemblies of a companion pair of davits, complete with lifeboat, being released to run downwardly on the roller tracks from their boatinboard to their boat-outboard or lowering positions, under the influence of gravity and the control of the brake associated with the aforementioned winch, wherefrom the fall-ropes are paid out in unison with each other.

Under all operating conditions, except against severe lists, that is to say, for all normal launchings the trips on the roller tracks are left in their inoperative positions, as shown in FIGS. 1 and 2, the arms thus remaining in their normal operative positions, also as shown in these figures being there retained by the coupling. Accordingly, the davits function in the manner common to orthodox davits of their kind, the angular displacement imparted to the arms by the tilting of the carriages, as they are lowered into the terminal sections of the roller tracks, being sufiicient to effect disengagement of the boat keel and pulley-block respectively from the supports 52 and slip-hooks 53, whereupon the boat, by further payingout of the fall-ropes, can be lowered to its embarkation position, and thence to the water. In FIGS. 1 and 2 the carriage and arm assembly, and the lifeboat, are shown in ful1-1ines in the boat-inboard position and in FIG. 1 in chain-dotted lines in the boat-outward position, the boat here being shown at or near embarkation level. Although FIGS. 1 and 2 show the davit under even-keel conditions they are nevertheless revelant, from the operational aspect, to the range of conditions referred to above.

However, in the contingency that the davits are required to operate against a severe list, such as that indicated in FIGS. 3 and 4, the trips on the roller tracks are turned into their operative positions so that the stops 36 engage the push-rods 34 on the carriages just as the last-mentioned are completing their downward run on the tracks, as shown in FIG. 5. The push-rods are thereby actuated to effect disengagement of the couplings 29 from the cross-bars 30, whereupon the companion davit arms are constrained, by the downward pull thereon of the lifeboat, simultaneously to outswing, under the control of the aforementioned brake, until the articulated ties are fully extended and the arms assume their extendedreach launching positions.

Initially, the outswinging movement of the arm is effected by the direct gravitational pull of the boat on the slip-hooks 53 at the tops of the arms, since the pulleyblocks are then in engagement with these hooks, and the boat, although overhanging the deck to an appreciable extent, is nevertheless positioned with its center of gravity outboard from the axle 20, as shown in FIG. 3. When the arms have outswung to the angle at which the pulleyblocks disengage from the slip-hooks, however, the projections 55 above the slip-hooks bear downwardly on the pulley-blocks and support the arms until they, the

4 arms, are finally supported in their outermost positions by the fully extended ties, whereupon the boat can be lowered to the embarkation level, as shown in FIG. 4, and thence to the water.

The degree of list shown in FIGS. 3 and 4 may be considered critical, being in the region of a ships capsizing point.

FIG. 5, in addition to showing the carriage just prior to completing its downward run on the roller track, with the trip in its operative position, shows, in full-lines, the lower part of the arm in its normal operative position on the carriage, the articulated tie in its retracted position and the coupling prior to its release from the crossbar on the carriage. This figure also shows, in chaindotted-lines, the lower part of the arm in its outermost position, and part of the link 24 of the tie, together with the coupling.

When retracting the arms from their outswung positions by means of the winch, for example, during drills or testing of the davit, the couplings will automatically re-engage the respective cross-bars to retain the arms in their normal operative positions on the carriages.

Referring now to FIG. 6, wherein relevant portions of the flush deck and ships side are shown respectively at 11 and 12, the davit in this example has two roller tracks 56 and 57 each formed, similarly to the track previously described, of two inturned channels. Of these, the main track 56 slopes straightly downwards from the top of an upstanding frame 58 to the ships side, and the secondary track 57 is curved and extends below the main track, between the frame 58 and the lower part of the main track, being additionally secured to the base beams 59 of the davit.

The roller carriage 60, in this case, is of triangulated form comprising two interconnected side plates, and having its roller axles 19 and 20 located at its two lower corners in such a way that the flange-rollers 18 on the axle 19 run on the main track and those on theax-le 20 on the secondary track. The cross-bar 30, and a now required pivot pin 61 for the link 25 of the articulated tie, are fitted within the upper corner of the carriage.

In this davit, the fall-rope 42, instead of passing directly between the pulley 46 at the top of the track 56 and the winch-cum-brake unit 47, is looped around an intermediate pulley 62 located on the underside of the main track, just above the secondary track.

Apart from the foregoing, the components of the davit shown in FIG. 6 are similar to those described with reference to FIGS. 1 to 5, and, accordingly, are indicated by the same reference numerals.

Operation of the davit just described is similar to that of the davit previously described, the carriage and arm assembly, with the arm in its normal operative position, tilting outwardly as it runs downwardly on the main 1track between the boat-inboard and boat-outboard posiions. In FIG. 6 the carriage and arm assembly, and the l feboat are shown in the boat-inboard position in fulllines, and in the boat-outboard position, with the arm outswung, in chain-dotted lines. The upper part of the arm, prior to its outswinging movement, is also shown in chain-dotted-lines in this figure.

Although not shown in FIG. 6, a trip, substantially as herein'before described, may be fitted to the davit for releasing the coupling 29 through the medium of a pushrod incorporated in the carriage, and a slip-bolt, indicated at 63, or other detent device, on the main roller track may be provided to prevent backward movement of the carriage after disengagement of the pulley-block from the slip-hook of the arm, particularly when the davit is operative against a severe list.

Modifications, within the scope of the invention as defined by the appended claims, may be made to the foregoing.

For instance, instead of, or additionally to, the trips, manually operable strikers adapted to release the couplings may be provided, or the couplings themselves may simply be adapted for direct manual release.

Further, if necessary or desirable, shock-absorbing means such as fluid-dashpots may be fitted in association with the arms or structures. These may be fitted between the pivot pins 26 of the articulated ties and pivotal mountings located, as the case may be, either at, or near, the carriage axles on which the arms are pivotal.

I claim:

1. A roller track gravity davit in which a boat supporting and suspending structure comprises a roller carria-ge movable between a boat-inboard position and a boat-outboard position, a davit anm pivotally mounted on said carriage and movable between a normal launching and an extended-reach launching position relative thereto, latching means for holding the davit arm in said normal-launching position when the carriage is in the boat-inboard position and the boat-outboard position, said latching means being releasable to allow the davit arm to move to said extended-reach launching position when the carriage is in the boat-outboard position, and stop means for holding the davit arm in said extended-reach launching position.

2. A davit according to claim 1, in which said latching means has co-operating coupling parts on the davit arm and the roller carriage.

3. A davit according to claim 2, in which said stop means comprises an articulated tie having its ends respectively pivotally connected to the carriage and davit arm.

4. A davit according to claim 3, in which the fallrope and pulley system therefor are so arranged that the davit arm can swing out under the control of a brake assisted by a winch of the davit, and can also be replaced into its normal position on the carriage by means of said winch.

5. A roller track gravity davit in which a boat supporting and suspending structure comprises a roller carriage movable between a boat-inboard position and a boat-outboard position, a davit arm pivotally mounted on said carriage and movable between a normal launching and an extended-reach launching position relative thereto, latching means for holding the davit arm in said normal-launching position when the carriage is in the boat-inboard position and the boat-outboard position, said latching means being releasable to allow the davit arm to move to said extended-reach launching position when the carriage is in the boat-outboard position, and stop means for holding the davit arm in said extended-reach launching position, said stop means comprising an articulated tie having its ends respectively pivotally connected to the carriage and davit arm.

References Cited by the Examiner UNITED STATES PATENTS 1,776,959 9/1930 Taylor 938 1,827,534 10/1931 McKenzie 9--39 2,667,649 2/1954 Elling 9---38 FOREIGN PATENTS 976,751 12/1964 Great Britain.

MILTON BUCHLER, Primary Examiner.

ALFRED E. CORRIGAN, Examiner. 

1. A ROLLER TRACK GRAVITY DAVIT IN WHICH A BOAT SUPPORTING AND SUSPENDING STRUCTURE COMPRISES A ROLLER CARRIAGE MOVABLE BETWEEN A BOAT-INBOARD POSITION AND A BOAT-OUTBOARD POSITION, A DAVIT ARM PIVOTALLY MOUNTED ON SAID CARRIAGE AND MOVABLE BETWEEN A NORMAL LAUNCHING AND AN EXTENDED-REACH LAUNCHING POSITION RELATIVE THERETO, LATCHING MEANS FOR HOLDING THE DAVIT ARM IN SAID NORMAL-LAUNCHING POSITION WHEN THE CARRIAGE IS IN THE BOAT-INBOARD POSITION AND THE BOAT-OUTBOARD POSITION, SAID LATCHING MEANS BEING RELEASABLE TO ALLOW THE DAVIT ARM TO MOVE TO SAID EXTENDED-REACH LAUNCHING POSITION WHEN THE CARRIAGE IS IN THE BOAT-OUTBOARD POSITION, AND STOP MEANS FOR HOLDING THE DAVIT ARM IN SAID EXTENDED-REACH LAUNCHING POSITION. 